Life Cycle of Wild Oats

Common oats

Avena fatua, or the common wild oat, is a type of oat native to Eurasia but has since migrated to most temperate regions of the world, carried by humans as they explored. Wild oats are considered a nuisance by many farmers as they invade field crops, lowering the quality of the good for sale as well as competing for nutrients in the soil.

Appearance

Wild oats resemble cultivated oats in appearance. It is a green grass with a hollow stem that ranges from 1 foot to 4 feet tall. The tip of the oat ends with a panicle (cluster of branches that generally holds flowers on plants) with spikelets (a small fauna spike that holds a seed). Long leaves are pressed against the stem, and generally hairy. Outside the spikelets, the seeds are also hairy, allowing them to stick to transportation mechanisms such as birds and human clothing.

Germination

Wild oats germinate in the growing season, primarily in the spring with a secondary period in the fall. This lasts one to three weeks, depending on weather. Warmth and humidity speeds up the germination, while cold and lack of moisture can prolong it. Germination requires the seed to be planted, although even just a scant covering of dirt (such as a centimeter or so) satisfies this requirement, allowing for conditions such as heavy rains to start the process.

Growth

The primary period of growth for wild oats lies throughout the first half of spring. Cool weather with a high degree of humidity provides the best survival conditions and rate of growth, leading to early crops being the most heavily infested (closest to the wet winter months). Growth starts out slow but speeds up after two weeks.

Flowers

Wild oats start flowering in early July (depending on when they were seeded) and can continue for a month and a half. Seeds at the tip of the panicle may leave the oat before the seeds at the base. When shed seeds fully mature, they shatter from the oats and spread. This is generally before the rest of the crop surrounding them mature, allowing for dispersal of seeds before tilling.

Reproduction

The seeds of the wild oat are dormant when they shatter. They can be activated by warm, dry conditions, such as a following summer, after ripening. If there is a source of moisture when they become active, they will germinate. If they do not germinate within a short period, they will become dormant again. 80 percent of seeds germinate the spring after seeding, 97 percent the second spring after, and the last 3 percent take up to 12 years due to deep-seated dormancy or bad location.

References

• UC Davis; Cover Crop Database